"Breeding-back" aims to restore or immitate extinct animals by selective breeding. This blog provides general information, the facts behind myths and news from various projects.

Monday, 18 September 2017

The horn of the last aurochs bull

The last
remnant population of aurochs was found in a Polish game reserve in possession
of the Polish crown from the 16th century until their extinction in
1627. From about 1600 onwards, the last aurochs were found exclusively in the
forest of Jaktorow. It was the first extinction of an animal that was precisely
documented. In 1564, the number of living aurochs was already as low as 38. In
1599, there were only 24 aurochs left. The 1602mentions only four individuals: three bulls and one cow. In 1620 it was reported
that the last aurochs bull had died and only one cow was left. In 1630, it was
noted that this very last cow died three years ago. I illustrated her
presumable lone death with a drawing and a little story here in 2015. The
reasons why the last aurochs could not survive were poaching and hunting,
cattle diseases, limited space and food as much as several severe winters the
aurochs could not cope with in their strongly restricted habitat.

It is a
myth that the last individual was hunted or poached, it is also a Wikipedia
fabrication that her skull was preserved and sent to the Royal Armoury of
Stockholm. Unfortunately no skeletal remains are known from these very recent
aurochs. But horns and skins of aurochs from Jaktorow were indeed preserved and
ornamented and sent to the nobility, and so was one of the horns of the last
aurochs bull.

Some weeks
ago I came across high-resulted images of this horn from several useful angles
on Wikipedia provided with detailed information by the Royal Armoury of
Stockholm.

What is
very apparent at first is that the horns are comparably thin and slim, fitting
a notion by Anton Schneeberger who visited the Jaktorow population in the 16th
century. Aurochs horns from earlier centuries are noticeable thicker and also
more curved (for example see here, a photo of medieval drink horns at
the National Museum of Copenhagen that might be of aurochs, by Markus Bühler).
The curvature seems indeed very meagre also compared to most bony core fossils
(which, logically, were still less curved than their horn sheaths that covered
them in life). See here, for example.

Even more
surprising are the size data for the horn given in the description. Apparently
it measures only 34,8 cm in length (!) and only 5,7 cm in diameter. I assume
that the bull was fully grown when it died, and even if it was a subadult bull,
the horn must have been still quite small proportionally for aurochs standards.
It is possible that the overall size of the last aurochs was smaller after all,
but Schneeberger still described them as way larger than domestic cattle.

The horns
of the last aurochs bull might have resembled those of this Maronesa bull,
though probably not oriented as lowly.

Why were
the horns of the last aurochs so small and meagre compared to those of earlier
centuries and millennia? I see two major factors. One would be trophy hunting.
Aurochs horns were regarded as prodigious trophies, and hunting for aurochs
with particularly large and impressive horns would be directive selective
pressure against such horns, eventually resulting in the horns becoming smaller
and less impressive. This effect of trophy hunting has also been observed in
elks and African elephants, although I have no written source at hand at the
moment. The other and probably more important factor would be the limited
habitat and therefore limited food supply. This would have led to a stint in
horn volume, especially if the mineral supply (calcium in particular), was low.
Perhaps the small size of the horns was partially due to phenotypic plasticity
and they would have grown larger horns if they had grown up on an area of
sufficient food and mineral supply, but I consider it very likely that much of
shrinkage in horn size also had a genetic component.

In any
case, it of course provokes the question if the “breeding-back” standards
should also include this meagre horn shape and size. I do not recommend it for
two reasons. At first, the causes of the meagre horns of the last aurochs
remnants were likely anthropogenic. Furthermore, most “breeding-back” results
have horns smaller and less curved than the overwhelming maturity of all
aurochs populations of all ages and regions, and permitting horns as small and
weakly curved as that of the last aurochs bulls might make it even more
difficult to move the average horn type found in “breeding-back” results
towards what was typical of most aurochs.

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About this blog

This blog is on everything related to the so-called “breeding-back” of extinct animals: From the extinct animals themselves, over their often domestic descendants and dedomestication to news and facts about various breeding-back projects, reports and photos from my own breeding-back related trips. I try to have a balanced and fact-based approach to this subject and to dismantle many of the popular myths. Enjoy!

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About me

My major interest always have been extinct animals, from dinosaurs to Pleistocene megafauna and more recent extinctions. Besides that I am interested in evolution, genetics and ecology.
I am also an amateur animal artist, making drawings and models mostly of extinct animals.